Development and evaluation of a video program for presentation prior to elective cardiac surgery.

BACKGROUND: : The objective of the present study was to develop and evaluate the effects of a preparatory videotape on endocrine stress responses of patients prior to cardiac surgery and to analyze patient acceptance of this video for preoperative preparation. METHODS: : 101 male patients prior to elective cardiac surgery were enrolled into the study. On the day before surgery, patients were assigned to one of the following groups: group 1 (n = 51) saw a video with realistic information about the upcoming perioperative procedure, and group 2 (n = 50) saw a video of the same length without surgery-related information. Venous blood was sampled before and 15 min after the video presentation. On the second postoperative day, patients filled in a questionnaire concerning their experiences of having preoperatively watched the video. RESULTS: : After viewing the video, blood levels of cortisol, adrenocorticotropic hormone (ACTH), beta-endorphin, prolactin, epinephrine and norepinephrine in patients of group 1 were not significantly different compared to values measured before the video presentation. In patients of group 2, blood levels of cortisol, ACTH, prolactin and norepinephrine were significantly lower after video presentation compared to values obtained before the video. Patients of group 1 (compared to group 2) were significantly more often of the opinion that the video had helped in the preparation for surgery, and that they would like to repeat this adjunct preoperative video preparation in another similar situation. CONCLUSION: : We conclude from our results that (i); cardiac surgical patients prefer preoperatively an adjunct surgery-related video preparation to a non-specific video presentation, and that (ii); preoperative preparation with realistic information about the upcoming medical procedure in patients undergoing cardiac surgery does not lead to an increase in endocrine stress hormone levels.

Inter-individual differences in cytokine release in patients undergoing cardiac surgery with cardiopulmonary bypass.

Cardiac surgery with cardiopulmonary bypass (CPB) leads to a systemic inflammatory response with secretion of cytokines (e.g. IL-6, TNF-alpha, IL-1 beta and sIL-2R). The objective of the following study was to investigate in vitro and in vivo cytokine responses and white blood cell counts (WBC) of patients with high versus low cytokine secretion after a coronary artery bypass grafting (CABG) procedure. Twenty male patients undergoing elective CABG surgery with CPB under general anaesthesia were enrolled in the study. On the day of surgery (postoperatively), serum levels of TNF-alpha and IL-1 beta were significantly higher in patients of the high IL-6 level group compared to the respective values in the patient group with low IL-6 levels. The inter-individual differences in IL-6 release in patients undergoing CABG surgery with CPB were accompanied by differences in the release of other cytokines, such as TNF-alpha, IL-1 beta and sIL-2R. To understand whether genetic background plays a role in influencing cytokine plasma levels under surgical stress, we examined the distribution of polymorphic elements within the promoter regions of the TNF-alpha and IL-6 genes, and determined their genotype regarding the BAT2 gene and TNF-beta intron polymorphisms. Our preliminary data suggests that regulatory polymorphisms in or near the TNF locus, more precisely the allele set 140/150 of the BAT2 microsatellite marker combined with the G allele at -308 of the TNF-alpha gene, could be one of the genetic constructions providing for a less sensitive response to various stimuli. Our results suggest: (1) close relationships between cytokine release in the postoperative period, and (2) inter-individually varying patterns of cytokine release in patients undergoing CABG surgery with CPB.

Irrigating fluid absorption during percutaneous nephrolithotripsy.

BACKGROUND: The most common complication during percutaneous nephrolithotripsy (PNL) is the destruction of organ structures with extravasation of the irrigation fluid into the retroperitoneal space. Consequently, there is an increased risk of a urosepsis and a complicated therapeutic course. In this study we aimed to show that extravascular absorption could be differentiated from intravascular absorption due to their unique absorption characteristics, and that these characteristics enable a prediction of possible post-operative complications. METHODS: In a prospective study of 31 patients with PNL, ethanol was added to the irrigating fluid and blood ethanol concentration (BEC) was measured by gas chromatography during the endoscopic procedure and in the recovery room. Following the guidelines of Hahn, patients were divided into two groups: group EVA, in whom extravasation had occurred with subsequent absorption; group IVA, those with intravascular absorption. Patients' post-operative progress along with diagnoses of renal perforations or bleeding, or signs of infection or sepsis, were comprehensively listed. RESULTS: EVA was diagnosed in 19 cases, and IVA in 12 cases. Maximum BEC levels were achieved after 20 min (median) in the IVA group, and 75 min in the EVA group (P < 0.05). Apart from their significantly higher demand for opioids (P < 0.05), EVA patients had been hospitalised for a substantially and significantly longer period of time (P < 0.01). Although without statistical significance, there was a higher rate of peri-operatively confirmed complications and prolonged intensive therapeutic treatment in the extravasation group. CONCLUSION: Retroperitoneal extravasation can be identified by using ethanol monitoring during and after PNL. Afflicted patients require considerably longer hospitalisation, probably because of the additional injury to surrounding organ structures.

Perioperative cytokine release during coronary artery bypass grafting in patients of different ages.

Surgical interventions and cardiopulmonary bypass (CPB) induce a systemic inflammatory response with cytokine release. Ageing is perceived as a process of impaired immune functions: IL-1beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) secretion are increased while IL-2 release is reduced in advanced age. At present, little information is available about perioperative immune reactions at different stages of ageing. The aim of the present study was to compare IL-6, IL-1beta, TNF-alpha, IL-10 and soluble IL-2 receptor (sIL-2R) in younger and older patients undergoing cardiac surgery. Male patients (n = 14) undergoing elective coronary artery bypass grafting (CABG) surgery employing CPB with moderate hypothermia were divided into two groups according to their age: group 1 included seven patients < 50 years old, group 2 included seven patients > 65 years old. All patients received general anaesthesia using a balanced technique with sufentanil, isoflurane and midazolam. Blood samples were collected pre-operatively (T1); intra-operatively during CPB (T2); post-operatively on the day of surgery (T3); on the first post-operative day (T4). Blood concentrations of IL-6, IL-1beta, IL-10, TNF-alpha and sIL-2R were measured using commercially available ELISA kits and corrected for plasma cell volume. Statistical analysis was performed by non-parametric analysis of variance and Mann-Whitney U-test. Significance level was set to P<0.05. There were no statistically significant differences in the perioperative release of TNF-alpha, IL-6, IL-1beta, IL-10 and sIL-2R among the two groups. We conclude that the perioperative course of cytokine release in patients undergoing CABG surgery with CPB and comparable perioperative management does not significantly differ in the two age groups.

[The effect of temperature and humidity on breath samples. Measurement of breath ethanol concentration in artificially respirated patients]. / Einfluss von Temperatur und Luftfeuchtigkeit auf die Probenentnahme. Messung der Atem-Alkoholkonzentration bei beatmeten Patienten.

UNLABELLED: When looking for the possible cause of distortions in values measured for the determination of breath ethanol concentration (BEC) in artificially respirated patients, consideration must be given to the humidity and temperature of the gas examined. In the present study, the effects of humidified and warmed and of dry and cold air on the accuracy of a newly developed BEC measuring device, as compared to a reference model and to a conventional system, were examined in a lung model. METHODS: A temperature-regulated pediatric incubator was used containing a 10 I gas reservoir and a breath humidifier with temperature regulated water bath. This setup provided constant temperature and humidity in the gas examined during measurement period. In the 'expiration' the air was directed from the breath humidifier through a measuring unit via a 'mouthpiece' into the reference system (Alcotest 7110, Dräger Inc., Lübeck) and then out. The measuring unit consisted of sensors for the temperature and relative humidity, and of a connector for the three sample extraction systems (PES). PES I was the conventional system with a 100-cm gas-sample pipe (Alcomed 3010), PES II the newly developed system (AlcoMed 3011, both from Envitec, Wismar) with a 10-cm gas-sample pipe, and PES III with a 20-cm heated gas-sample pipe. During 'inspiration' 2 l of air was fed into the system to rinse the measuring unit and to fill the reservoir. 61 measurements were performed with dry and cold air, and 71 with humidified and warmed air, in the course of which the ethanol concentration was increased from 0 to 1.5/1000. Data were evaluated using regression analysis and the Bland & Altman method. RESULTS AND CONCLUSIONS: The constancy of the values set for temperature, relative humidity and absolute humidity in the lung model was given for all measurements. In the dry and cold air, the results from all three test systems coincided almost perfectly with the reference values. The measured BEC in the humidified and warmed air using sample-extraction systems II and III corresponded to a high degree with the reference, while in the case of PES I, only a moderate linear correlation was achieved. The temperature and humidity of the expired gas during artificial respiration influence the gas samples extracted for the purposes of BEC measurement. Newly developed sample-extraction systems II and III coincide with the reference system, even under respiration-simulated gas conditions.

Effects of propofol vs isoflurane on respiratory gas exchange during laparoscopic cholecystectomy.

BACKGROUND: Respiratory function and pulmonary gas exchange are affected in laparoscopic procedures where a pneumoperitoneum is introduced using CO2. Previous studies have shown differing results concerning pulmonary gas exchange during laparoscopic procedures: Whereas in patients undergoing isoflurane anaesthesia decreases in PaO2 are demonstrated, this factor remains unchanged in patients undergoing propofol anaesthesia. In the present study, the effects of propofol on pulmonary gas exchange were compared with those of isoflurane in patients undergoing elective laparoscopic cholecystectomy in a prospective randomised manner. METHODS: Twenty ASA patients with physical status I and II were divided randomly between isoflurane (IG) and propofol groups (PG). After induction of anaesthesia patients were moderately hyperventilated. Respirator settings remained unchanged during pneumoperitoneum (PP) until 10 min after deflation of the peritoneal cavity. Blood gas analyses were performed at 5 time points: 15 min after induction of anaesthesia (giving pre-PP values), immediately before carbon dioxide insufflation (0 min PP), after both 30 and 60 min of PP and 10 min post PP. Inspiration plateau pressure (Pplat), compliance of the respiratory system, and both ins- and expiratory gas concentrations were continuously recorded by an Ultima V monitor (Datex Corp., Helsinki, Finland). The difference between arterial and end-tidal CO2 partial pressure (P(a-et)CO2) was calculated so as to allow assessment of physiological dead space by the modified Bohr equation. RESULTS: Pulmonary gas exchange differed significantly after 30 min of PP between the IG and the PG. At this time, PaO2 was 19.5 +/- 2.9 kPa (mean +/- SD) in the IG and 23.1 +/- 1.8 kPa in the PG (P < 0.01), whereas PaCO2 was 5.5 +/- 0.37 kPa in the IG and 4.9 +/- 0.27 kPa in the PG (P < 0.01). These discrepancies remained until after carbon dioxide desufflation. At 10 min post PP, PaO2 was 18.3 +/- 2.6 kPa in the isoflurane group and 21.9 +/- 2.2 kPa in the propofol group (P < 0.01), whereas PaCO2 was 5.4 +/- 0.46 kPa in the IG and 4.8 +/- 0.22 kPa in the PG (P < 0.01). During carbon dioxide insufflation the P(a-et)CO2 increased significantly in the IG from 0.47 +/- 0.13 kPa to 0.76 +/- 0.37 kPa (P < 0.05), while the values in the PG remained constant. CONCLUSION: This study demonstrates that pulmonary gas exchange in patients with laparoscopic cholecystectomy is affected by the choice of anaesthetic procedure. During and after laparoscopic cholecystectomy using isoflurane as the anaesthetic, the PaCO2 is significantly higher and the PaO2 significantly lower than they are with propofol.